Hi acey,
The Free Multiround is a tier-based event. Both of the players in question were recently promoted in the last 2 days, but were in the proper tier when they posted their first round scores. Despite being promoted to the next tier they will still have to compete with their previous tier's clubs for the 2nd round of that event. They will compete in their new tiers in any future tournaments or ranked stroke play rounds.
Even if you gain a promotion mid-tourney you always remain competing in the old tier. You're just restricted to using the lower tier clubs for the duration of those events because it wouldn't be fair to allow a player to use Master tier clubs in a Pro level event.